(Manuscript received 27 April 2017; accepted for publication 28 September 2017)

Abstract. In this study reserve endosperm proteins, hordeins of seven spring barley cultivars with different origin: Zernogradskii (Russia), Bodega, Fink, Scarlett and Barke (Germany), Josefin and Astoria (France) were fractionated and characterized by SDS-PAGE electrophoresis. On the basis of the obtained spectra 19 bands (D + C + B) with different relative electrophoretic mobility and intensity were identified. The electrophoresis profiles of the groups D-, C- and B- hordein are designated as separate types (models) using the index corresponding to hordein blocks. We have established one profile type for D-hordein (D1), two- for C-hordein (C1, C2), and five – for B-hordein (B1, B2, B3, B4, B5). Based on these results hordein formulas (configurations) of accessions are constructed, which enable the expression of specific varietal characteristics and prove the existence of the inter allelic variation (hordein polymorphism) due to the presence or absence of protein components and their different electrophoretic mobility in the profiles of D-, C- and B-hordein.

Abstract. The aim of this study was to investigate the loss of accuracy of AC-method for milk yield control in sheep under the conditions of threefold milking per day. Test day milk yield records of 113 ewes raised on sheep farm of the Agricultural University in Plovdiv collected according to official A4 method were used. Two breeds were raised at the university experimental farm: White Maritza (49 ewes) and Patch Faced Maritza (64 ewes). Predicted milk yield data on test day were simulated using different prediction coefficients (calculated at morning, noon or evening milk recording). Database includes 2577 predicted milk yield records on test day. The loss of accuracy using AC method is accumulated in two ways: by milk yield prediction coefficients on test day and milk yield calculations during milking period. Loss of accuracy (LA1) in prediction of test day milk yield by prediction coefficients varies from 10.02% to 12.74% according to type of milk recording (morning, noon or evening). Three factors such as level of test day milk yield, type of milk recording and animal have larger influence on LA1, 27.70%, 21.99% and 19.32%, respectively, of total variation. Loss of accuracy (LA2) in the calculated total milked milk per milking period on the basis of predicted test day milk yield according to the morning, noon and evening milk recordings compared with A4 method are 7.04%, 8.03% and 6.05%, respectively. Depending on the type of milk recording on the test day (morning, noon and evening), 46.88% to 56.15 % of the observations of LA2 fall within the scope of ±5%. Rank correlations in the ranking of ewes in all years and different designs of AC method have high values from 0.891 to 1.000.

Abstract. The study was conducted to examine the variation in the agronomic and morphological traits in spring barley. For this purpose, 22 lines from the ICARDA High Input Barley Program for favorable environment and 3 check varieties (Rihane-03, VMorales and Veslets) were tested in an alpha-lattice design with two replications at the Institute of Agriculture – Karnobat, Bulgaria in 2014 and 2015 growing season. The traits days to heading, plant height, number of tillers per plant, flag leaf length, flag leaf width, spike length, awn length, peduncle length, spikelet number per spike, grain number per spike, grain weight per spike, 1000 grains weight, grain yield, powdery mildew (Erysiphe graminis f. sp. hordei), net blotch (Pyrenophora teres f. teres) and stripe rust (Puccinia striiformis f. sp. hordei) infection were studied. Significant differences between lines for all studied traits were found. The number of fertile tillers per plant was significantly positively correlated with grain yield. Lines expressed higher grain yields, shorter stem, better tolerance to net blotch and stripe rust than Bulgarian check variety Veslets were identified. These genotypes can, therefore, be used as parents for the improvement of spring barley.

Institute of Roses, Essential and Medical Cultures, Kazanlak, Bulgaria (Manuscript received 12 June 2017; accepted for publication 25 August 2017)

Abstract. The purpose of this research is to develop effective protocol for clonal micro propagation of the oil-bearing rose (Rosa damascena Mill.). Explants used in the experiment are 1.0 to 1.5 cm long nodal segments from specially cultivated mother plants. These explants were subjected to a combined method of sterilization with 0.2% solution of HgCI2 for 3 minutes followed by 0.50% solution of NaClO for 20 minutes and 0.25% solution of NaClO for 30 minutes. The best results of multiplication were obtained in basic MS medium with added BAP quantity of 0.5 to 3.0 mg/L. After being separated from the mother plants the young shoots are placed directly in compost mixture for rooting and adaptation. Thus the process of multiplication is shortened, avoiding the period of in vitro rooting.

Abstract. For accelerated development of fertility restorer lines with imidazolinone tolerance in sunflower (Helianthus annuus L.), the gamma-induced parthenogenesis, which combines classical breeding approaches and in vitro techniques, was applied. As initial materials six imidazolinone-tolerant hybrid combinations (F1203, F1216, F1246, F1248, F1295 and F1332), obtained from Dobrudzha Agricultural Institute, General Toshevo, were used. To initiate parthenogenetic development mixed pollen from different fertility restorer lines was applied. The mixed pollen was irradiated with a dose of 600 Gy. A total of 166 parthenogenetic immature embryos were obtained, and 84 young plants developed from them, 42 of the plants were fertile. Best parthenogenetic response, expressed as a number of embryos obtained, was observed by hybrid combination F1295, followed by hybrid combination F1332. The lowest parthenogenetic responsiveness is reported in hybrid combinations F1246 and F1248, where the total number of parthenogenetic embryos obtained was 5. In hybrid combinations F1295 and F1332, as well as in F1216, the method of gamma-induced parthenogenesis can be efficiently used for accelerated production of parental lines for heterosis breeding in sunflower. In hybrid combinations F1203, F1246 and F1248, which showed low parthenogenetic responsiveness, conventional methods for developing lines from these hybrids are recommended.

(Manuscript received 7 February 2017; accepted for publication publication 31 May 2017)

Abstract. Seeds of Hordeum vulgare L. cultivar Izgrev were treated with different concentrations of sodium azide to induce genetic variability for the selection of genotypes with improved traits. After passing through different stages of selection, 18 promising mutants were selected for further studies. Eighteen mutants and their parent and national standard cultivar Veslets were evaluated in Complete Block Design with four replications. The research was conducted in 2013 – 2014 and 2014 – 2015 growing seasons in the experimental field of the Institute of Agriculture Karnobat, Southeastern Bulgaria. The characters studied included days to heading, plant height, lodging, peduncle length, spike length, awn length, spikelet number per spike, grain number per spike, grain weight per spike, 1000 grains weight and grain yield. Wide variation among mutant lines was observed for different traits. Mutant lines M4/16 and M3/14 produced significantly greater grain yield than the parent and standard cultivar. Positive changes in lodging tolerance, grain number per spike, grain weight per spike, 1000 grains weight were also observed. This study showed positive effects in the use of mutation in inducing improvement for grain yield and some yield related traits.

(Manuscript received 7 February 2017; accepted for publication 30 May 2017)

Abstract. Ahil is a new winter malting barley cultivar developed by the method of experimental mutagenesis at the Institute of Agriculture, Karnobat, Bulgaria. Biological and agronomic characteristics of the cultivar were also investigated for several years and at the Executive Agency of Varietal Testing, Field Inspection and Seed Control trails in the period 2012 – 2013. Averaged for 6 locations in Bulgaria grain yield of the new cultivar was significantly higher than the yield of standard cultivars with about 5%. At the Institute of Agriculture grain yield was 17% higher than the average standard for the period of 5 years. The cultivar has high winter hardness, lodging resistance, resistance to powdery mildew and medium resistance to brown rust. Ahil has good malting quality.

(Manuscript received 29 September 2016; accepted for publication 30 January 2017)

Abstract. Nitrogen uptake and expense of durum wheat were studied under the conditions of fertilized field experiment on soil type Pellic vertisol. The seven genotypes – Progress, Vazhod, Victoria, Predel, Deana, Zvezdica and Elbrus selected at the Institute of Field Crops – Chirpan, Bulgaria, were grown in two field crops rotation of cotton and durum wheat under rainfed conditions for a period of three vegetations in years 2011-2013. The spring treatments of nitrogen as NH4NO3 were as follows: N0, N60, N120 and N180. The total N uptake in the above ground biomass of durum wheat increased with the amount of applied nitrogen and during climatically favorable years reached 220 kg N.ha-1. A tendency was found that the new genotypes uptook more N, compared to varieties Progress and Vazhod. The N expense of the new cultivars Predel and Zvezdica showed the highest amount of N per 1 ton of grain, 40.7 and 41.1 kg, respectively. Strong positive correlation was found between N fertilization and N uptake and expense for 1 ton of grain. The regression model indicated that N uptake with the grain and straw and N expense depending on N fertilization occurred with delay. With N fertilization of durum wheat at rates of up to 180 kg N.ha-1 each kilogram of applied N fertilizer increased the average expected N uptake with 7 kg.ha-1 and N expense with 0.66 kg.ton-1 grain.

Agricultural Research and Development Station Teleorman, Drăgănești Vlașca, 147135 Teleorman, Romania (Manuscript received 11 October 2016; accepted for publication 19 January 2017)

Abstract. The purpose of the paper was to identify new peas genotypes, created in Agricultural Research and Development Station, Teleorman, South Romania, with improved productivity and adaptability to the environmental conditions of that region. The study was carried out with 25 field pea varieties for a period of three years (2013-2015). The experiment was conducted in randomized complete blocks design in three replications. The results of variance analysis showed that there was significant difference among pea genotypes by grain yield. The average yield over three years showed that lines M 1357, M 1410, M 1418 and M 720 achieved higher yield levels compared with the control genotype Vedea and with the average yield of all tested genotypes. Yields stability was estimated by coefficient of variability. Correlation analysis showed that the strongest relations there are between productivity elements: number of pods and seeds per plant (r = 0.905), number of pods and seeds weight per plant (r = 0.655), number of seeds per plant and seeds weight (r = 0.815), plant height and first pod insertion height (r = 0.921). There are significant negative correlations between 1000 seeds weight and number of grains per plant (r = – 0.229), number of pods per plant and 1000 seeds weight (r = -0.346), the first pod insertion height and number of pods per plant (r = -0.530), and the number of grains per plant (r = -0.412). The results obtained in this study suggest that, the new field pea genotypes are suitable for spreading and cultivating in Southern Romania.

Abstract. During the period 2012 – 2014, a second cycle of recurrent selection of early flowering in a synthetic maize population “Exotic-07” was conducted and finished on the experimental field of Maize Research institute – Knezha. The experiments are carried out by a block method, on a test plot of 10 m2, with three replications, and the respective for the region agricultural equipment. Twenty-three progeny from the first and second cycle, the source and improved exotic maize populations, as well as their testcrosses with the lines ХМ 4416 and PAU 1617 are tested. A phenotypic cycle assumes a leading position in terms of dates of plant silking as the forms of the earliest flowering are used as pollen in the population. The selected early flowering forms are sown for inbreeding and forming an improved maize population. As a direct result of the work of improvement, progeny with a period of days until silking averagely shorter with 5 days and grainmoistureloweredby1.1%areobtained.Theaimofthisstudyistopointoutinbredlineswithashortervegetativeperiodandusethemasparental forms for obtaining high-yielding mid-late maize hybrids.

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p-ISSN: 1313-8820
e-ISSN: 1314-412X

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Agricultural Science and Technology /AST/ was founded in 2009 by Faculty of Agriculture, Trakia University,
Stara Zagora, Bulgaria.
It’s is published in English in one volume of 4 issues per year, as a printed journal and in electronic form.

All issues in 2017 are printed with the financial support of the Project No DNP 05-21/20.12.2016, financed by Fund ‘Scientific Research’ grant Bulgarian scientific Periodicals.